Cooled bottom electrode for electric smelting-furnaces.



M. SPERLING. COOLED BOTTOM ELECTRODE FOR ELECTRIC SMELTING FURNACES.

APPLICATION FILED NOV. 13, 1914.

1,234,947. Patented J uly 31, 1917.

STATES PATENT OFFICE.

MARTIN SPERLING, OF ESSEN-ON-THE-RUHR, GERMANY, ASSIGNOR TO FRIED. KRUPPAKTIENGESELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

GOOLED BOTTOM ELECTRODE FOR ELECTRIC SMELTING-FURNACES.

Specification of Letters Patent.

Patented July 31, 1917.

Application filed November 13, 1914. Serial No. 871,969.

ing. is a specification.

In electric furnaces the bottom electrodes must be prevented frommelting or glowing by means of artificial cooling. For this purpose, ithas been'customary to widen the cross section of the electrodesdownward, and to make the lower end of the electrodes hollow, so that acooling fluid may be leel through. The electric current enters at thelowermost end of the electrodes.

It has been noted, that of a number of such bottom electrodes, connectedin parallel, some few .explode and consequently destroy the smeltingfurnace. The object of the present inventlon is now to prevent withcertainty the described disturbances.

The invention is based on the knowledge, that the explosions are causedsimply by excessive load of current and not, as was sup- 1 posed for along time, by the heat from the smelting bath. Such overload mayhowever, be accounted for by the occasional interruption of theconductivity between the bottom electrodes and the smelting bathoccurring simultaneously in a greater number of electrodes throughclinker or other portions of the furnace lining, such as dolomite. Theother electrodes then have to carry a current load, which isconsiderably in excess of the calculated amount, and which will soonbring into incandescence the lowermost annular portion of theelectrodes, sprinkled by the cooling fluid. The consequences of this, isdecomposition of the cooling water and the formation of oxyhydrogen gas,which explains the violent explocompanying drawings where In accordancewith the }present invention, the circuit connects with t at portion ofthe electrode which is situated between the fluidcontaining part and thehead piece of the electrode.

The invention is illustrated in the Figure 1 shows a vertical sectionthrough an electrode-furnace, indicatin the posi tion of the electrodesin the mace bottom, and

Fig. 2 an elevation and part section in larger scale of one embodimentof the invention.

Referring more particularly to Fig. 1, A

denotes the hearth of the smelting furnace,

B the main electrodes composed of carbon and suspended over the furnace,G the smelting bath and D the bottom electrodes of wrought iron arrangedin a circle and built into the bottom of the smelting furnace. Each ofthese is provided with a cooling cap D beneath the furnace bottom. Thecorresponding cooling fluid supply and discharge conduits are indicatedby E and E respectively.

The electrode bodies have a cylindrical head piece (5 at their upperend, followed by a widening conical portion a cylindrical portion 0Z anda collar (F. To this is bolted the already mentioned cooling cap D. Thiscap incloses, with a slight clearance, the lowermost, threaded end d ofthe electrode body, see Fig. 2. The cooling fluid, which fiows throughthe'threads in the direction indicated by the arrows on and x then comesin contact with a comparatively great area of the surface to be cooledof the electrode end (i On the upper side of the collar d are boltedcover plates F of bronze for leading in the current.

- The conical widening of the electrodebody serves, in accordance withthe present invention, not only to provide necessary space for thecooling fluid, as is customary with known electrodes, butiit causes atthe same time, the current density in the electrode-body to decreasetoward the lower end. Under otherwise similar conditions, an electrodeconstructed in accordance with the present invention will therefore beheated considerably less, than an electrode, which, as heretoforecustomary, has a lower hollow portion through which the'current flows,to permiteflective cooling. In any case, parts, which come in directcontact with the cool- 1ng fluld, can never become incandescent, duringvery much stronger overload of current.

I claim: 1. In an electric smelting furnace'having upper and lowerelectrodes, the lower one the connection of the current conductor.

,. them; and means'for giving thefluid a cir-.

2. In an electric smelting furnace having upper and lower-electrodes,the lower one of ,said electrodes comprising a head, a central portion,and a cooling fluid-containing portion; said central portion being usedfor the connection of the current conductor; and said coolingfluid-containing portion having a cap and a core member inclosed by saidcap'so as to leave a slight-clearance between them for guiding the fluidcircuitously in a downward direction. I

3. In an electric smelting furnace having upper and lower electrodes,the lower one of said electrodes comprising a head, a central portion,and a cooling-fluid-containing portion; said central portion being usedfor the connection of the current conductor; saidcooling-fluid-containing portion having a cap and a core member inclosedby said cap so as to leave a slight clearance between cuitous patharound'said core member.

4. In an electric smelting furnace having upper and lower electrodes,the lower one of said electrodes comprising a head, a central portion,and a cooling'fluid-containing portion; said central portion being usedfor cal path through said cap.

the connection of the current conductor; said cooling fluid-containingportion having a cap with a fluid inlet at the topand an outlet at thebottom, and a core member inclosed by said cap so as to leave a slightclearance between them, said cap being rigidly secured to said centralportion; and means for causing the fluid to take a heli- 5, Inanelectric smelting furnace having upper and lower electrodes, the lowerone of said electrodes comprising a head, a central portion, and acooling-fluid-containing portion; said central portion being used forthe connection of the current conductor; said cooling-fluid-containingportion having a cap with a fluid inlet at the top and outlet at t ebottom, and a core member inclosed by said cap so as to leave a slightclearance between them, said cap'bein rigidly secured to said centralportion; an said core member i lbiein provided with screw threads.

MARTIN SPERLING. [n.a] In presence of HELEN Norma, ALBERT NUFER.

oregoing specification signed at- .Barmen, Germany, this 2nd day ofOctober,

